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Title
Cassandra database agent properties -
Description
This is a full list and explanation of the configurable properties of the Foglight for Cassandra agent. The Agent Installer Wizard provides access to the essential subset of available properties. To modify other properties or modify the agent configuration after creation, use the Agent Status dashboard.
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Resolution
DB Connection
The agent requires a connection to the cluster in order to gather information about the cluster and data structure. The agent may be referred to other nodes than the one specified.
- IP or Hostname – Host where Cassandra node is running. Default is “localhost”. (e.g. or )
- Port – The CQL native transport port for the Cassandra node. Default is 9042.
- Username – User that can connect to the Cassandra node. Password – Password of the user that can connect to the Cassandra node.
- Use TLS/SSL? – Whether the database connection should be made over SSL.
JMX Connections
The agent requires JMX access to individual nodes in the cluster to gather most operational metrics.
- Node Connections – IP/Hostname for each node in the cluster to be monitored must be added to this list. Values for the columns Port, Username, and Password can be specified for each node if they differ. If no value is provided for these, values will be taken from the default fields under JMX Connections (see below). Check "Use as Host Alias?" to indicate that the value provided for "IP or Hostname" should be used as an alias for the discovered hostname for the respective node. Secondary Property Lists are global and can be shared between agents. To create a new property list for a different cluster, clone an existing list and then edit and save it as the selected list for that agent.
- Default Port – JMX listening port for the Cassandra node. This value will be used as the default value in the Node Connections list if no other value is provided. Default is 7199.
- Default Username – JMX User that can connect to the Cassandra node. This value will be used as the default value in the Node Connections list if no other value is provided.
- Default Password – Password of the JMX User that can connect to the Cassandra node. This value will be used as the default value in the Node Connections list if no other value is provided.
Collection Periods
The Collection Interval fields in the agent properties are used to set the sample frequencies. You can turn off a collection by setting the interval to 0. The defaults are set based on the type of data being collected for relevancy.
- Availability – Controls the query interval for node availability collections.
- Cluster and Node – Controls the query interval for cluster and node collections over the database driver.
- Keyspace and Table – Controls the query interval for keyspace and table collections over the database driver.
- JMX Cluster – Controls the query interval for cluster metrics over JMX.
- JMX Keyspace – Controls the query interval for keyspace metrics over JMX. If Max Tables is set to zero keyspace metrics are not collected.
- JMX Table – Controls the query interval for table metrics over JMX. If Max Tables is set to a positive value, metrics controlled by this period are collected for the largest tables only. If Max Tables is equal to zero this period is not used. If Max Tables is set to -1 this period is used to collect metrics from all tables.
- JMX Table Size – Controls the query interval for table size metrics over JMX. If Max Tables is set to a positive value, metrics controlled by this period are collected for all tables for the purpose of determining the largest tables on the cluster. If Max Tables is less than or equal to zero this period is not used.
- Slow Query – Controls the query interval for collection of the DSE Slow Query log.
- Trace – Controls the query interval for collection of the trace log. Note that tracing must be enabled on the Cassandra instance(s) separately for data to be collected.
- JVM – Controls the query interval for the JVM collections over JMX.
Options
Host Aliases
Aliases can optionally be added for Cassandra nodes in case hostnames as discovered by the agent differ from those used for the Hosts monitor. This Secondary Property List is a pairing of the uniquely identifying Host ID (a UUID string) and the desired hostname alias. There are two ways to determine a node’s Host ID for use in the Aliases list. For a node that has already been monitored for some time, the Host ID can be found on the Nodes Table of the Cassandra Clusters dashboard (the Host ID column is hidden by default, so it will need to be made visible via the table's "Show columns" dialog). Host IDs can also be queried directly from a specific Cassandra instance with the following CQL:
SELECT host_id FROM system.local WHERE key='local';
Contact Points
Additional contact points for the database driver to assist with making an initial connection if the node specified by the main contact point is not available.
Max Traces/Queries
The maximum number of traces or slow query entries to collect per their respective collection periods. Limiting the number here prevents the FMS from being overwhelmed by data (particularly from traces) on very active instances.
Max Tables
The number of tables for which to collect full metrics. If set to 0, no keyspace or table metrics are collected. If set to the default of -1, full metrics are collected for all tables.